Support is requested for participation in all clinical and laboratory investigative activities of the Pediatric Oncology Group (POG). Specifically, these funds will assist our efforts in cooperative cancer therapy trials which utilize a combination of surgery and/or radiation therapy and/or chemotherapy for the treatment of leukemias, lymphomas, solid tumors and brain tumors. Emphasis will be placed on integrated multi-modality treatment programs in Phase III randomized prospective studies. We shall also participate in group-wide Phase II studies of new chemotherapeutic agents. We plan to participate fully in limited Pediatric Phase I studies of new agents. (This is the subject of a contract proposal from several POG institutions, including ourselves, to the NCI). We shall participate in studies examining the biology of various pediatric malignancies including immunologic and pharmacologic features; in studies of the late effects of therapy in surviving patients; and in epidemiological studies. Support will permit us to enter the maximum number of patients on study and ensure complete documentation of patient data, including transport of specimens to reference laboratories. It will permit members to attend POG meetings and to participate in working sub-committees, protocol planning committees and study writing committees. In addition it will permit certain investigators to continue to contribute in leadership roles to the science and administration of the POG. Dr. V. Michael Whitehead is Co-Chairman of the New Agents & Pharmacology Scientific Support Committee. In this position, he directs Phase I and Phase II new agent studies. He is developing protocols to study the pharmacology of methotrexate, 6-mercaptopurine and cytosine arabinoside in children with acute lymphoblastic leukemia. He is a member of the Planning Committee for ALinC 14, the next frontline therapeutic study of acute lymphoblastic leukemia. Dr. Carol Freeman is Coordinator of the Phase I study of Hyperfractionation in Brainstem Gliomas in Children (POG 8495) and a member of the following POG committees: Institutional Performance Review Committee and the Brain Tumor Core Committee. Dr. Penny Koch is a member of the Bone Marrow Transplant Core Committee. Susan Kajaks is a member of the Data Managers Core Committee.